High-performance supercapacitors materials prepared via in situ growth of NiAl-layered double hydroxide nanoflakes on well-activated graphene nanosheets

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• 作者：Niu Yulian^a ; Li Ruiyi^b ; Li Zaijun^a ; ^{zaijunli@263.net} ; Fang Yinjun^c ; Liu Junkang^a
• 关键词：Graphene ; NiAl-layered double hydroxides ; Supercapacitors ; Electrochemical performance
• 刊名：Electrochimica Acta
• 出版年：2013
• 出版时间：1 April, 2013
• 年：2013
• 卷：94
• 期：Complete
• 页码：360-366
• 全文大小：1103 K

文摘

High-performance supercapacitors materials (a-GNS/NiAl-LDH) was fabricated via in situ growth of NiAl-layered double hydroxide (NiAl-LDH) nanoflakes on well-activated graphene nanosheets (a-GNS). Graphene oxide was exfoliated and reduced using the microwave irradiation, alkali corrosion and thermal annealing in sequence. The resulting a-GNS is of large BET surface area of up to 3026 m² g^?1 and excellent conductivity. The as-prepared a-GNS/NiAl-LDH was characterized by scanning electron microscope, transmission electron microscope, X-ray diffraction and infrared spectrum. The results indicated NiAl-LDH nanoflakes are well dispersed on the wrinkled graphene nanosheets. Further, the apparent electron transfer rate constant (k_s) and electrochemical performance of a-GNS/NiAl-LDH as electrode material for supercapactiors were also investigated. The k_s value was found to be 0.0885 cm s^?1, which is more than 2.5-fold that of pure NiAl-LDH. The a-GNS/NiAl-LDH provides a maximum specific capacitance of 1730.2 F g^?1 at current density of 0.1 A g^?1. The specific capacitance can remain 790 A g^?1 when the current density increase to 10 A g^?1, which is more than 6- and 3-fold that of pure NiAl-LDH (116.3 F g^?1) and common GNS/NiAL-LDH (260.6 F g^?1) made from the graphene produced by the chemical reduction of graphene oxide, respectively. The capacitance can keep at least 99.2 % at current density of 5 A g^?1 after 500 cycles. These demonstrated that the use of a-GNS obviously improve the specific capacitance, high-current capacitive behavior and cycle stability.